Relier Pairs Talking About FunctionsVersion en ligne Matching par Logos Sprachinstitut 1 The purpose of the wheel is to steer the truck. 2 The shelf is bolted to the wall with screws. 3 The function of the switch is to turn the machine on and off. 4 The bridge is supported by steel pylons. 5 The airflow is regulated by the valve. 6 The vehicle is powered by the engine. 7 The purpose of the backup file is to keep our data safe. Screws bolt the shelf to the wall. The valve regulates the airflow. The wheel steers the truck. The engine powers the vehicle. The switch turns the machine on and off. The backup file keeps our data safe. Steel pylons support the bridge.